Computers are known to include a central processing unit (“CPU”), main memory, system buses, and a plurality of supporting units. Such supporting units include audio processing circuitry, video processing circuitry, graphical user interface modules, etc. Physically, many of the supporting units are mounted or coupled to a motherboard. Each of the supporting units, when coupled to the motherboard, includes a local bus that couples the supporting unit to the system bus.
In operation, when the CPU is inputting, or outputting, data from a supporting unit, it generates an address and a command, which are provided on the system bus. Each of the supporting units, via its local bus, monitors the address bus to determine whether the particular command is directed to it. When the appropriate supporting unit detects that the command is for it, it performs the command. If the command is to input data, the supporting unit stores, and processes—if instructed—, the data provided by the CPU. If the command is to output data, the supporting unit outputs the data via the local bus to the system bus and routes it either to the CPU, or a designated recipient.
In a typical computer, the video graphics processing circuitry is on a separate board than the audio processing circuitry. As such, the video graphics circuit board and the audio processing circuit board each have their own local buses. In addition, they each require coupling to the motherboard and function as totally independent circuits. A typical audio processing circuit board will retail for approximately $30.00, which, in turn, relates to approximately $15.00 of manufacturing costs. With the ever-increasing demand for smaller, more powerful, and less expensive computers, it would be desirable to reduce the cost of including an audio processing circuit.
Therefore, a need exists for a method and apparatus of a graphics circuit and audio processing circuit contained on a single chip and/or printed circuit board.